Today's vehicle navigation systems are essentially made up of the subsystems digital road map, computing module for calculating the route, position determination, system management, vehicle sensory system for detecting vehicle movements, and an input unit and an output unit for operating it and navigating. The digital road map is usually available on a storage medium, e.g. a navigation CD-ROM, in the vehicle. After the destination is input, the navigation system determines the route on the basis of the available map material. The calculated route is used for the navigation. If the driver leaves the current route during the trip, then the navigation device determines a new route on the basis of the current position.